1. Field of the Invention
The present invention relates to heatable hair curlers for curling human hair. More particularly, the invention relates to a novel adjustable apparatus for curling hair with curlers of selected diameters which may be stored and carried in a small volume.
2. The Background Art
Hair curlers are well known. Such devices traditionally comprise a cylinder upon which hair is rolled or curled. Heat and/or hair spray or other hair products are often applied so that the hair takes on the shape of the curler and, when the curler is removed, the hair is still curled. It is often desirable to be able to adjust the diameter of a curler so that a small number of curlers may offer the capability of curling at a number of diameters. A number of adjustable diameter curlers are thus known in the art. U.S. Pat. No. 4,456,020 to van Deursen teaches an adjustable diameter curler. The van Deursen device comprises a pair of telescoping elongated tubes axially and rotatably movable relative to one another. A pair of nested larger diameter end caps is secured at each end of each tube with the roller generally resembling a spool. Each pair of end caps includes a first cap with spiralled cam slots radiating from its center and a second cap nested in the first with a plurality of corresponding or equal number of straight cam slots radiating from its center. The nesting caps are rotatable relative to each other and the caps at each end are connected together by a plurality of toothed elongated curler segments. Each segment has structure at each end cooperating with the cap slots such that by rotating the end caps in opposite directions the segments are radially cammed to change the curler roller diameter. Additional structure locks the cap rotation at any desired roller diameter.
U.S. Pat. No. 5,186,187 to Roberts teaches another adjustable diameter curler. Roberts' device provides for the use of a cylindrical tube rolled from a rectangular perforated sheet of flexible material, the sheet having an outer edge which overlaps a portion of the tube. The tube has a pair of opposing transverse edges, each of which is engaged within a spiral groove formed in opposing caps. The caps are rotationally mounted on an elongated shaft, such that rotation of the disks causes advancement of the transverse edges within the spiral groove, changing the diameter of the outer tube, as desired.
U.S. Pat. Nos. 5,020,552 and 4,856,542 to Hollenberg et al. teach a radially expandable hair curler comprising a generally cylindrical hollow body, a detachable holding strap stretching from one longitudinal end of the body to the other, and internal mechanical devices for expanding and contracting the curler body.
U.S. Pat. No. 4,270,555 to Punte teaches a hair curler that provides for a plurality of stages of hair curling with increasing wave lengths along the length of the hairs of the head. The hair curler may be used on short hair or very long hair. The multi-stages provide for a selectivity of lengths for short hair. The hair curler consists of a plurality of removably insertable curler components that nest one within the other in a manner similar to a telescoping mechanism. An elastic tie provides a means for securing the plurality of removably insertable components together and, at the same time, holds the hair in place on the curler. A port hole in one end provides a means for applying wave solution to the hair rolled on the interior of the roller, with communicating slots to permit the solution to seep through to the hair at the periphery of the spiraling rolls of hair.
U.S. Pat. No. 5,000,200 to Roberts provides for the use of a cylindrical tube rolled from a rectangular sheet of flexible material, the sheet having an outer edge which overlaps a portion of the tube. The tube has a pair of opposing transverse edges, each of which is engaged within a spiral groove formed in opposing end caps. The end caps are rotationally mounted on an elongated shaft, such that rotation of the caps causes advancement of the transverse edges within the spiral grooves, changing the diameter of the outer tube, as desired.
U.S. Pat. No. 3,232,300 to Fisher teaches an adjustable diameter hair curler formed of a sheet of soft plastic having an array of holes and a line of snap-type fasteners. The snaps mate with and penetrate a line of holes in the array to hold the sheet in the form of a cylinder. Diameter adjustment is accomplished by selecting another line of holes to apply the snaps to.
Non-adjustable fixed-diameter cylindrical hair curlers are known which include hook-type fasteners on the outer portion of the cylinder for engaging hair.
U.S. Pat. No. 4,584,462 to Morrison teaches a transportable heating unit for hair curlers which utilizes a heat sink core to heat a plurality of hair curler elements stored longitudinally adjacent to the heat sink core. The heat must pass through an insulating layer of the curler elements.
While the foregoing devices are fit for their intended purposes, there is room for improvement in portable, adjustable diameter heated hair curlers.